Ferrous alloy



UNITED STATES PATENT OFFICE.

FERROUS ALLOY Walter E. Jominy, Detroit, Mich., assignor to GeneralMotors Corporation, Detroit, Mich., a corporation of Delaware NoDrawing. Application November 5, 1938, Serial No. 239,022

6 Claims. (Cl. 75126) This application relates to ferrous alloys andcast irons which would, of course, be rather difllmore particularly tocast iron compositions which cult to machine. have very good propertiesof wear resistance. There are many instances when other specific Thealloys forming the subject matter of the properties in addition to theability to resist wear 4 present invention possess the resistance toscorare required in a cast iron. Such a property as 5 ing characteristicof cast iron and have extra high strength in larger size casings, aswell as good properties as regards resistance to wear good hardness nearthe center of large castings. under severe conditions, The alloys inaccordis frequently essential. Also, in many cases it n w th myinvention are especially adapted is highly desirable that the iron haveextra good for such parts as cylinder liners, piston rings, fluidity atordinary casting temperatures and/or pistons, Valves, valve guides,tappets, bearings be easily m l in h p l In ny cases and other partsordinarily subjected to w ar, it is highly desirable that the casting beleak The invention comprises alloys composed of es carbon, silicon,titanium, copper, manganese, The following compositions having theesseni chromium. and iron as essential constituents. ial t u nts in appmat y th p p Ordinary impurities as sulphur, phosphorus, etc., tionsstated have been found especially good as are present in small amounts.For example, the rd resistance to W In bars 78" X 1 x sulphur is usuallypresent from a, tra up t 12" cast in green sand molds these compositions.12%. In some cases slightly greater amounts, are readily machinable-The Several examples I say up to may be present without unduly giveneach have good resistance to wear and 20 affecting the beneficialeffects of the essential a w so va o in ot des e p y a constituents. Thephosphorus is ordinarily kept p p low, that is, under about .20%.However, higher mp O- 1 amounts up to about 1% may be present 2.86%carbon, 2.18% silicon, .16% titanium.

5 The several essential constituents are in ap- 94% copper. 52%manganese, 51% chromium,

proximately the following proportions: 2.25- balance on 4.00% carbon,l.50-3.50% silicon, .05-.60% tita- Exam 1 Na 2 nium, .501.50% copper,.30-1.00% manganese, 1 .40-2.00% chromium, balanc m 3.17% carbon, 2.29%silicon, .14% titan um,

l A preferred narrower range of the essential coPperi manganesechmmmm'ingredients is the following: 2.7s 3.75% carbon, balance 2.oo-3.20%silicon, .10 .45% titanium, .55-1.1o% Example 3 copper, -30% m nganese,.2 chro- 3.26% carbon, 2.61%. silicon, 28% titanium, miu b e iron- .99%copper, 55% manganese, 1.13% chromium,

i In addition to the ability to resist scoring and balance iron. 35

wear, the alloys of my invention are ordinarily Example No. 4

comparatively easy to machine. It will be understood by those skilled inthe art that the carbon and silicon content may be modified within theranges given to suit the casting size and/or Example 5 cooling rate inorderto obtain extremely good machinability. It is common knowledge inthe 326% carbOn, 251% 511mm iltaniumi field of metallurgy that smallcastings by reason Copper manganfesei 113% chromlumi of their fastercooling will have more combined phosphorus Palance 'f carbon and lessgraphitic carbon than will cast- The several alloymg Qstltuents may be Pings of large size when both are made of the same corpora? anyconvenwjnt mannerchemical composition. Higher combined carbon gardsconvement f F P and less graphitic carbon will make machining ing thesame is 1n the form of a silicon titanium more diflicult so that thecomposition must be alloy- Order to redufie the Penfiency 0f themodified to compensate for this condition This titanium to becomeoxidized, it is preferably may be done by adding more silicon, moreearadded at a late stage in the melting process. If bon, or more of b thil d a b n, desired to add silicon late to get higher strength Withinthe range of composition given it is it is permissible. Any suitablemelting furnace possible in certain section sizes to obtain white may beused,

2.90% carbon, 2.38% silicon, 26% titanium, 1.05% copper, .49% manganese,1.19% chromium,

balance iron. 0

I claim: i

1. An alloy comprising the following elements as essential constituentsin approximately the amounts stated: 2.25-4.00% carbon, 1.50-3.50%silicon, .05-.60% titanium, .50-1.50% copper, .30-

1.00% manganese, .40-2.00% chromium, balance substantially all iron.

.2. An alloy composed of the following elements as essentialons'tituentsin approximately the amounts given: 2.75%-3.75% carbon, 2.00-3.20%silicon, .10-.4.-5% titanium, .55-1.10% copper, .40- .80% manganese,.50-1.25% chromium, balance 'iron.

3. An alloy composed oi the following elements as essential constituentsin approximately the proportions given: 2.86% carbon, 2.18% silicon,

.16% titanium, .94% copper, .62% manganese, .51% chromium, balance iron.

4. An alloy composed of the following elements as essential constituentsin approximately the proportions given: 3.17% carbon, 2.29% silicon,.14% titanium, 58% copper, 114% manganese,

58% chromium, balance iron.

